The present invention relates to a side seal and a linear guide apparatus including the same.
Conventionally, a linear guide apparatus (linear guide) is provided with side seals at the both ends of a slider in the movement direction so that a foreign matter does not enter the inside of the slider. Such a side seal includes a metal plate referred to as a cored bar, which is attached and fixed to the slider with screws and a body portion fixed to the metal plate by adhesion, the body portion including a lip portion coming into sliding contact with a guide rail. Then, the side seal having such a configuration is disposed so as to fill the gap between the guide rail and an end cap attached to each of the both ends of the slider.
Therefore, the above-described lip portion prevents the foreign matter on the top face or the side face of the guide rail from entering the inside of the slider when the slider relatively moves with respect to the guide rail.
Moreover, as illustrated in FIG. 5, in conventional side seals, there are often provided with “gaps 134” between a lip portion 133 and a guide rail 110, the gaps 134 being located at positions other than a necessary contact portion, so as to prevent the contact portion between the lip portion 133 and the guide rail 110 from being a surface increasing the sliding friction. Similarly, a “relief portion 135” is often provided at the circumference of the lip portion 133 so as to provide the lip portion 133 with freedom in deformation in order to avoid a strong contact with the guide rail 110 and so as not to increase the sliding friction.
In this situation, an under seal can be disposed on the bottom face of the slider corresponding to an opening side of the slider having a letter U shape, so as to fill the gap between the slider and the guide rail and prevent the entrance of the foreign matter from the guide rail.
However, the side seal has a substantially letter U shape almost the same as the shape of the end cap in a plane perpendicular to the moving direction (axial direction) of the slider. An end portion of the lip portion disposed along the outer circumference of the guide rail is positioned at the opening side of the slider. Therefore, there is a possibility of the entrance of the foreign matter or the outflow of the lubricant, since the “relief portion” and the “gap” communicate with the inside of the slider.
Therefore, as a solution, PTL 1 disclose a technique in which an auxiliary lip portion 114 is formed on side seal S facing an inner seal 104 and the under seal 105, the auxiliary lip portion 114 filling the gap formed between the end portion of the inner seal 104 or the under seal 105 and the slope of the side seal S.